Feathered Friends out in Seattle Washington has been turning out quality down gear since 1972. The Hummingbird Nano 20 is no exception. It’s the slimmest cut bag in their lineup and one of the lightest weighing in at 1 lbs. 12 oz. Just because it’s light doesn’t mean it won’t keep you warm. The Humminbird Nano is rated down to 20 degrees and has 850+ goose down fill. If you are looking for a light weight, three season bag look no further.